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US 7,185,619 B2Granted
Rocker arm and method of manufacturing the same
AssigneeKoyo Seiko Co., Ltd.
InventorNobutsuna Motohashi
Life of this patent
Estimating the term…
Abstract
A rocker arm 1 made of sheet metal is formed so that Vickers hardness Hv of the surface layer portion 9a of the valve stem receiver 9 is set at Hv 650 to 800 and a quantity of the retained austenite γR is set at 25 to 35 vol %.
Claims20
A rocker arm comprising:
- a valve stem receiver comprising sheet metal of low carbon steel, said valve stem receiver including a sliding contact face, wherein a valve stem slides and contacts said valve stem receiver,
- wherein Vickers hardness of a surface layer portion of said sliding contact face comprises a range of Hv 650 to 800, and a quantity of retained austenite of the surface layer portion of said sliding contact face comprises a range of γR 25 to 35 vol %.
A method of manufacturing a rocker arm comprising sheet metal of low carbon steel, the method comprising:
- performing treatment of carburizing, quenching and tempering with respect to a valve stem receiver of the rocker arm such that Vickers hardness of a surface layer portion of a sliding contact face of the valve stem receiver comprises a range of Hv 650 to 800, and a quantity of retained austenite of the surface layer portion of said sliding contact face comprises a range of γR 25 to 35 vol %.
A method of manufacturing a rocker arm comprising sheet metal of low carbon steel, the method comprising:
- welding a valve stem receiver to said rocker arm;
- and
- performing treatment of carburizing, quenching and tempering to adjust Vickers hardness of a surface layer portion of a sliding contact face of said valve stem receiver to comprise a range of Hv 650 to 800, and to adjust a quantity of the retained austenite of the surface layer portion of said valve stem receiver to a range of γR 25 to 35 vol %.
Dependencies are inferred from the claim text.